Wafer-level light emitting diode package and method of fabricating the same

ABSTRACT

A light emitting diode (LED) package includes a semiconductor stack including a first semiconductor layer, a second semiconductor layer, and an active layer disposed between the first and second semiconductor layers, the first and second semiconductor layers having different conductivity types, a first contact layer disposed on the first semiconductor layer, a second contact layer disposed on the second semiconductor layer, a first insulation layer contacting the first contact layer, a second insulation layer disposed on the first insulation layer, a first bump disposed on a first side of the semiconductor stack, the first bump being electrically connected to the first contact layer, a second bump disposed on the first side of the semiconductor stack, the second bump being electrically connected to the second contact layer, and a third insulation layer disposed on side surfaces of the first bump and the second bump.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/194,317, filed on Jul. 29, 2011, and claims priority fromand the benefit of Korean Patent Application No. 10-2010-0092807, filedon Sep. 24, 2010, and Korean Patent Application No. 10-2010-0092808,filed on Sep. 24, 2010, which are hereby incorporated by reference forall purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a light emitting diode package and a method offabricating the same and, more particularly, to a wafer-level lightemitting diode package and a method of fabricating the same.

2. Description of the Background

A light emitting diode (LED) is a semiconductor device that includes anN-type semiconductor and a P-type semiconductor, and emits light throughrecombination of holes and electrons. Such an LED has been used in awide range of applications such as display devices, traffic lights, andbacklight units. Further, considering the potential merits of lowerpower consumption and longer lifespan than existing electric bulbs orfluorescent lamps, the application range of LEDs has been expanded togeneral lighting by replacing existing incandescent lamps andfluorescent lamps.

The LED may be used in an LED module. The LED module is manufacturedthrough a process of fabricating an LED chip at a wafer level, apackaging process, and a modulation process. Specifically, semiconductorlayers are grown on a substrate such as a sapphire substrate, andsubjected to a wafer-level patterning process to fabricate LED chipshaving electrode pads, followed by division into individual chips (chipfabrication process). Then, after mounting the individual chips on alead frame or a printed circuit board, the electrode pads areelectrically connected to lead terminals via bonding wires, and the LEDchips are covered by a molding member, thereby providing an LED package(packaging process). Then, the LED package is mounted on a circuit boardsuch as a metal core printed circuit board (MC-PCB), thereby providingan LED module such as a light source module (modulation process).

In the packaging process, a housing and/or the molding member may beprovided to the LED chip to protect the LED chip from the externalenvironment. In addition, a phosphor may be contained in the moldingmember to convert light emitted by the LED chip so that the LED packagemay emit a white light, thereby providing a white LED package. Such awhite LED package may be mounted on the circuit board such as the MC-PCBand a secondary lens may be provided to the LED package to adjustorientation characteristics of light emitted from the LED package,thereby providing a desired white LED module.

However, it may be difficult to achieve miniaturization and satisfactoryheat dissipation of the conventional LED package including the leadframe or printed circuit board. Furthermore, luminous efficiency of theLED may be deteriorated due to absorption of light by the lead frame orthe printed circuit board, electric resistance heating by the leadterminals, and the like.

In addition, the chip fabrication process, the packaging process, andthe modulation process may be separately carried out, thereby increasingtime and costs for manufacturing the LED module.

Meanwhile, alternating current (AC) LEDs have been produced andmarketed. The AC LED includes an LED directly connected to an AC powersource to permit continuous emission of light. One example of AC LEDs,which can be used by being directly connected to a high voltage AC powersource, is disclosed in U.S. Pat. No. 7,417,259, issued to Sakai, et.al.

According to U.S. Pat. No. 7,417,259, LED elements are arranged in atwo-dimensional pattern on an insulating substrate, for example, asapphire substrate, and are connected in series to form LED arrays. TheLED arrays are connected in series to each other, thereby providing alight emitting device that can be operated at high voltage. Further,such LED arrays may be connected in reverse parallel to each other onthe sapphire substrate, thereby providing a single-chip light emittingdevice that can be operated to continuously emit light using an AC powersupply.

Since the AC-LED includes light emitting cells on a growth substrate,for example, on a sapphire substrate, the AC-LED restricts the structureof the light emitting cells and may limit improvement of lightextraction efficiency. Thus, investigation has been made into a lightemitting diode, for example, an AC-LED that is based on a substrateseparation process and includes light emitting cells connected in seriesto each other.

SUMMARY OF THE INVENTION

Exemplary embodiments of the invention provide a wafer-level LED packageand a method of fabricating the same, which can be directly formed in amodule on a circuit board without using a conventional lead frame orprinted circuit board.

Exemplary embodiments of the invention also provide a wafer-level LEDpackage and a method of fabricating the same, which has high efficiencyand exhibits improved heat dissipation.

Exemplary embodiments of the invention also provide a method offabricating an LED package, which may reduce manufacturing time and costof an LED module.

Exemplary embodiments of the invention also provide an LED module and amethod of fabricating the same, which has high efficiency and exhibitsimproved heat dissipation.

Exemplary embodiments of the invention also provide a wafer-level lightemitting diode package and a method of fabricating the same, whichincludes a plurality of light emitting cells and may be directly formedin a module on a circuit board without using a conventional lead frameor printed circuit board.

Additional features of the invention will be set forth in thedescription which follows and in part will be apparent from thedescription, or may be learned by practice of the invention.

An exemplary embodiment of the present invention discloses an LEDpackage including: a semiconductor stack including a first conductivetype semiconductor layer, an active layer, and a second conductive typesemiconductor layer; a plurality of contact holes arranged in the secondconductive type semiconductor layer and the active layer, the contactholes exposing the first conductive type semiconductor layer; a firstbump arranged on a first side of the semiconductor stack, the first bumpbeing electrically connected to the first conductive type semiconductorlayer via the plurality of contact holes; a second bump arranged on thefirst side of the semiconductor stack, the second bump beingelectrically connected to the second conductive type semiconductorlayer; and a protective insulation layer covering a sidewall of thesemiconductor stack.

An exemplary embodiment of the present invention also discloses a lightemitting diode module including the LED package according to theaforementioned exemplary embodiments. The LED module may include acircuit board; the LED package mounted on the circuit board; and a lensto adjust an orientation angle of light emitted from the LED package.

An exemplary embodiment of the present invention also discloses a methodof fabricating an LED package. The method includes forming asemiconductor stack including a first conductive type semiconductorlayer, an active layer, and a second conductive type semiconductor layeron a first substrate; patterning the semiconductor stack to form a chipseparation region; patterning the second conductive type semiconductorlayer and the active layer to form a plurality of contact holes exposingthe first conductive type semiconductor layer; forming a protectiveinsulation layer covering a sidewall of the semiconductor stack in thechip separation region; and forming a first bump and a second bump onthe semiconductor stack. The first bump is electrically connected to thefirst conductive type semiconductor layer via the plurality of contactholes, and the second bump is electrically connected to the secondconductive type semiconductor layer.

An exemplary embodiment of the present invention also discloses a lightemitting diode package. The LED package includes a plurality of lightemitting cells each including a first conductive type semiconductorlayer, an active layer, and a second conductive type semiconductorlayer; a plurality of contact holes arranged in the second conductivetype semiconductor layer and the active layer of each of the lightemitting cells, the contact holes exposing the first conductive typesemiconductor layer thereof; a protective insulation layer covering asidewall of each of the light emitting cells; a connector locatedarranged on a first side of the light emitting cells and electricallyconnecting two adjacent light emitting cells to each other; a first bumparranged on the first side of the light emitting cells and electricallyconnected to the first conductive type semiconductor layer via theplurality of contact holes of a first light emitting cell of the lightemitting cells; and a second bump arranged in the first side of thelight emitting cells and electrically connected to the second conductivetype semiconductor layer of a second light emitting cell of the lightemitting cells.

An exemplary embodiment of the present invention also discloses a lightemitting diode module including the LED package described above. Themodule includes a circuit board; the LED package arranged on the circuitboard; and a lens to adjust an orientation angle of light emitted fromthe LED package.

An exemplary embodiment of the present invention also discloses a methodof fabricating an LED package including a plurality of light emittingcells. The method includes forming a semiconductor stack including afirst conductive type semiconductor layer, an active layer, and a secondconductive type semiconductor layer on a first substrate; patterning thesemiconductor stack to form a chip separation region and a lightemitting cell separation region; patterning the second conductive typesemiconductor layer and the active layer to form a plurality of lightemitting cells, each light emitting cell having a plurality of contactholes exposing the first conductive type semiconductor layer; forming aprotective insulation layer covering a sidewall of the semiconductorstack in the chip separation region and the light emitting cellseparation region; forming a connector connecting adjacent lightemitting cells in series to each other; and forming a first bump and asecond bump on the plurality of light emitting cells. Here, the firstbump is electrically connected to the first conductive typesemiconductor layer via the plurality of contact holes of a first lightemitting cell of the light emitting cells, and the second bump iselectrically connected to the second conductive type semiconductor layerof a second light emitting cell of the light emitting cells.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate exemplary embodiments of theinvention, and together with the description serve to explain theprinciples of the invention.

FIG. 1 is a schematic sectional view of a light emitting diode packageaccording to a first exemplary embodiment of the invention.

FIG. 2 is a schematic sectional view of a light emitting diode packageaccording to a second exemplary embodiment of the invention.

FIG. 3 is a sectional view of a light emitting diode module includingthe light emitting diode package according to the first exemplaryembodiment.

FIG. 4 to FIG. 12 show a method of fabricating the light emitting diodepackage according to the first exemplary embodiment, in which (a) is aplan view and (b) is a sectional view taken along line A-A of (a) inFIG. 5 to FIG. 10.

FIG. 13 is a sectional view showing a method of fabricating the lightemitting diode package according to the second exemplary embodiment ofthe invention.

FIG. 14 is a schematic sectional view of a light emitting diode packageaccording to a third exemplary embodiment of the invention.

FIG. 15 is a schematic sectional view of a light emitting diode packageaccording to a fourth exemplary embodiment of the invention.

FIG. 16 is a sectional view of a light emitting diode module includingthe light emitting diode package according to the third exemplaryembodiment.

FIG. 17 to FIG. 26 show a method of fabricating the light emitting diodepackage according to the third exemplary embodiment, in which (a) is aplan view and (b) is a sectional view taken along line A-A of (a) inFIG. 18 to FIG. 23.

FIG. 27 is a sectional view showing a method of fabricating the lightemitting diode package according to the fourth exemplary embodiment ofthe invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The invention is described more fully hereinafter with reference to theaccompanying drawings, in which exemplary embodiments of the inventionare shown. This invention may, however, be embodied in many differentforms and should not be construed as limited to the exemplaryembodiments set forth herein. Rather, these exemplary embodiments areprovided so that this disclosure is thorough and will fully convey thescope of the invention to those skilled in the art. In the drawings, thesizes and relative sizes of layers and regions may be exaggerated forclarity. Like reference numerals in the drawings denote like elements.

It will be understood that when an element such as a layer, film, regionor substrate is referred to as being “on” another element, it can bedirectly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” another element, there are no intervening elements present.

FIG. 1 is a schematic sectional view of an LED package 100 according toa first exemplary embodiment of the invention.

Referring to FIG. 1, the LED package 100 may include a semiconductorstack 30, a first contact layer 35, a second contact layer 31, a firstinsulation layer 33, a second insulation layer 37, a first electrode pad39 a, a second electrode pad 39 b, a first bump 45 a, and a second bump45 b. The LED package 100 may further include an insulation layer 43, adummy bump 45 c, and a wavelength convertor 51.

The semiconductor stack 30 includes a first conductive type uppersemiconductor layer 25, an active layer 27, and a second conductive typelower semiconductor layer 29. The active layer 27 is interposed betweenthe upper and lower semiconductor layers 25, 29.

The active layer 27 and the upper and lower semiconductor layers 25, 29may be composed of a III-N based compound semiconductor, for example,(Al, Ga, In)N semiconductor. Each of the upper and lower semiconductorlayers 25, 29 may be a single layer or multiple layers. For example, theupper and/or lower semiconductor layers 25, 29 may include a superlattice layer in addition to a contact layer and a clad layer. Theactive layer 27 may have a single quantum well structure or amulti-quantum well structure. The first conductive type may be an n-typeand the second conductive type may be a p-type. Alternatively, the firstconductive type may be a p-type and the second conductive type may be ann-type. Since the upper semiconductor layer 25 can be formed of ann-type semiconductor layer having relatively low specific resistance,the upper semiconductor layer 25 may have a relatively high thickness.Therefore, a roughened surface R may be formed on an upper surface ofthe upper semiconductor layer 25, in which the roughened surface Renhances extraction efficiency of light generated in the active layer27.

The semiconductor stack 30 has a plurality of contact holes 30 a (seeFIG. 5( b)) formed through the second conductive type lowersemiconductor layer 29 and the active layer 27 to expose the firstconductive type upper semiconductor layer, and the first contact layer35 contacts the first conductive type upper semiconductor layer 25exposed in the plurality of contact holes.

The second contact layer 31 contacts the second conductive type lowersemiconductor layer 29. The second contact layer 31 includes areflective metal layer to reflect light generated in the active layer27. Further, the second contact layer 31 may form an ohmic contact withthe second conductive type lower semiconductor layer 29.

The first insulation layer 33 covers the second contact layer 31.Further, the first insulation layer 33 covers a sidewall of thesemiconductor stack 30 exposed in the plurality of contact holes 30 a.In addition, the first insulation layer 33 may cover a side surface ofthe semiconductor stack 30. The first insulation layer 33 insulates thefirst contact layer 35 from the second contact layer 31 while insulatingthe second conductive type lower semiconductor layer 29 and the activelayer 27 exposed in the plurality of contact holes 30 a from the firstcontact layer 35. The first insulation layer 33 may be composed of asingle layer or multiple layers, such as a silicon oxide or siliconnitride film. Alternatively, the first insulation layer 33 may becomposed of a distributed Bragg reflector, which is formed byalternately stacking insulation layers having different indices ofrefraction, for example, SiO₂/TiO₂ or SiO₂/Nb₂O₅.

The first contact layer 35 is located under the first insulation layer33 and contacts the first conductive type upper semiconductor layer 25through the first insulation layer 33 in the plurality of contact holes30 a. The first contact layer 35 includes contact sections 35 acontacting the first conductive type upper semiconductor layer 25, and aconnecting section 35 b connecting the contact sections 35 a to eachother. Therefore, the contact sections 35 a are electrically connectedto each other by the connecting section 35 b. The first contact layer 35is formed under some regions of the first insulation layer 33 and may becomposed of a reflective metal layer.

The second insulation layer 37 covers the first contact layer 35 underthe first contact layer 35. In addition, the second insulation layer 37covers the first insulation layer 33 while covering a side surface ofthe semiconductor stack 30. The second insulation layer 37 may becomposed of a single layer or multiple layers. Further, the secondinsulation layer 37 may be a distributed Bragg reflector.

The first and second electrode pads 39 a, 39 b are located under thesecond insulation layer 37. The first electrode pad 39 a may beconnected to the first contact layer 35 through the second insulationlayer 37. Further, the second electrode pad 39 b may be connected to thesecond contact layer 31 through the second insulation layer 37 and thefirst insulation layer 33.

The first bump 45 a and the second bump 45 b are located under the firstand second electrode pads 39 a, 39 b to be connected thereto,respectively. The first and second bumps 45 a, 45 b may be formed byplating. The first and second bumps 45 a, 45 b are terminalselectrically connected to a circuit board such as an MC-PCB and havecoplanar distal ends. In addition, the first electrode pad 39 a may beformed at the same level as that of the second electrode pad 39 b, sothat the first bump 45 a and the second bump 45 b may also be formed onthe same plane. Therefore, the first and second bumps 45 a, 45 b mayhave the same height.

Meanwhile, the dummy bump 45 c may be located between the first bump 45a and the second bump 45 b. The dummy bump 45 c may be formed togetherwith the first and second bumps 45 a and 45 b to provide a heat passagefor discharging heat from the semiconductor stack 30.

The insulation layer 43 may cover side surfaces of the first and secondbumps 45 a, 45 b. The insulation layer 43 may also cover a side surfaceof the dummy bump 45 c. In addition, the insulation layer 43 fillsspaces between the first bump 45 a, the second bump 45 b and the dummybump 45 c to prevent moisture from entering the semiconductor stack 30from outside. The insulation layer 43 also covers side surfaces of thefirst and second electrode pads 39 a, 39 b to protect the first andsecond electrode pads 39 a, 39 b from external environmental factorssuch as moisture. Although the insulation layer 43 may be configured tocover the overall side surfaces of the first and second bumps 45 a, 45b, the invention is not limited thereto. Alternatively, the insulationlayer 43 may cover the side surfaces of the first and second bumps 45 a,45 b except for some regions of the side surface near distal ends of thefirst and second bumps.

In the present exemplary embodiment, the insulation layer 43 isillustrated as covering the side surfaces of the first and secondelectrode pads 39 a and 39 b, but the invention is not limited thereto.Alternatively, another insulation layer may be used to cover the firstand second electrode pads 39 a, 39 b and the insulation layer 43 may beformed under the other insulation layer. In this case, the first andsecond bumps 45 a, 45 b may be connected to the first and secondelectrode pads 39 a, 39 b through the other insulation layer.

The wavelength convertor 51 may be located on the first conductive typeupper semiconductor layer 25 opposite to the rest of the semiconductorstack 30. The wavelength convertor 51 may contact an upper surface ofthe first conductive type upper semiconductor layer 25. The wavelengthconvertor 51 may be a phosphor sheet having a uniform thickness withoutbeing limited thereto. Alternatively, the wavelength converter 51 may bea substrate, for example, a sapphire substrate or a silicon substrate,which is doped with an impurity for wavelength conversion.

In the present exemplary embodiment, the side surface of thesemiconductor stack 30 is covered with a protective insulation layer.The protective insulation layer may include, for example, the firstinsulation layer 33 and/or the second insulation layer 37. In addition,the first contact layer 35 may be covered with the second insulationlayer 37 to be protected from an external environment and the secondcontact layer 31 may be covered with the first insulation layer 33 andthe second insulation layer 37 to be protected from an externalenvironment. The first and second electrode pads 39 a, 39 b are alsoprotected by, for example, the insulation layer 43. Accordingly, it ispossible to prevent deterioration of the semiconductor stack 30 due tomoisture.

The wavelength convertor 51 may be attached to the first conductive typeupper semiconductor layer 25 at a wafer-level, and then divided togetherwith the protective insulation layer during a chip separation process.Therefore, a side surface of the wavelength convertor 51 may be in aline with the protective insulation layer. That is, the side surface ofthe wavelength converter 51 may be flush along a straight line with aside surface of the protective insulation layer. Further, the sidesurface of the wavelength convertor 51 may be in a line with a sidesurface of the insulation layer 43. Thus, the side surfaces of thewavelength converter 51, the protective insulation layer, and theinsulation layer 43 may all be flush along a straight line.

FIG. 2 is a schematic sectional view of a light emitting diode package200 according to a second exemplary embodiment of the invention.

Referring to FIG. 2, the LED package 200 is similar to the LED package100 according to the above exemplary embodiment. In the presentexemplary embodiment, however, first and second bumps 65 a, 65 b areformed in a substrate 61.

Specifically, the substrate 61 includes through-holes, which have thefirst and second bumps 65 a, 65 b formed therein, respectively. Thesubstrate 61 is an insulation substrate, for example, a sapphiresubstrate or a silicon substrate, but is not limited thereto. Thesubstrate 61 having the first and second bumps 65 a, 65 b may beattached to a first electrode pad 39 a and a second electrode pad 39 b.In this case, to prevent the first and second electrode pads 39 a, 39 bfrom being exposed to the outside, an insulation layer 49 may cover sidesurfaces and bottom surfaces of the first and second electrode pads 39a, 39 b. Further, the insulation layer 49 may have openings, whichexpose the first and second electrode pads 39 a, 39 b, and additionalmetal layers 67 a, 67 b are then formed in the openings. The additionalmetal layers 67 a, 67 b may be composed of a bonding metal.

FIG. 3 is a sectional view of a light emitting diode module includingthe LED package 100 according to the first exemplary embodiment.

Referring to FIG. 3, the LED module includes a circuit board 71, forexample, an MC-PCB, the LED package 100, and a lens 81. The circuitboard 71, for example, the MC-PCB, has connection pads 73 a, 73 b formounting the LED packages 100 thereon. The first and second bumps 45 a,45 b (see FIG. 1) of the LED package 100 are connected to the connectionpads 73 a, 73 b, respectively.

A plurality of LED packages 100 may be mounted on the circuit board 71and the lens 81 may be disposed on the LED packages 100 to adjust anorientation angle of light emitted from the LED packages 100.

In accordance with the second exemplary embodiment, the light emittingdiode packages 200 may be mounted on the circuit board instead of theLED packages 100.

FIG. 4 to FIG. 12 show a method of fabricating the LED package 100according to the first exemplary embodiment. In FIG. 5 to FIG. 10, (a)is a plan view and (b) is a sectional view taken along line A-A of (a).

Referring to FIG. 4, a semiconductor stack 30, which includes a firstconductive type semiconductor layer 25, an active layer 27 and a secondconductive type semiconductor layer 29, is formed on a growth substrate21. The growth substrate 21 may be a sapphire substrate but is notlimited thereto. Alternatively, the growth substrate 21 may be anotherkind of heterogeneous substrate, for example, a silicon substrate. Eachof the first and second conductive type semiconductor layers 25, 29 maybe composed of a single layer or multiple layers. Further, the activelayer 27 may have a single-quantum well structure or multi-quantum wellstructure.

The compound semiconductor layers may be formed of III-N based compoundsemiconductor on the growth substrate 21 by metal organic chemical vapordeposition (MOCVD) or molecular beam epitaxy (MBE).

A buffer layer (not shown) may be formed before forming the compoundsemiconductor layers. The buffer layer is formed to relieve latticemismatch between the growth substrate 21 and the compound semiconductorlayers and may be formed of a GaN-based material layer such as galliumnitride or aluminum nitride.

Referring to (a) and (b) of FIG. 5, the semiconductor stack 30 ispatterned to form a chip (package) separation region 30 b whilepatterning the second conductive type semiconductor layer 29 and theactive layer 27 to form a plurality of contact holes 30 a exposing thefirst conductive type semiconductor layer 25. The semiconductor stack 30may be patterned by photolithography and etching processes.

The chip separation region 30 b is a region for dividing the LED packagestructure into individual LED packages and side surfaces of the firstconductive type semiconductor layer 25, the active layer 27 and thesecond conductive type semiconductor layer 29 are exposed on the chipseparation region 30 b. Advantageously, the chip separation region 30 bmay be configured to expose the substrate 21 without being limitedthereto.

The plurality of contact holes 30 a may have a circular shape, but isnot limited thereto. The contact holes 30 may have a variety of shapes.The second conductive type semiconductor layer 29 and the active layer27 are exposed to sidewalls of the plurality of contact holes 30 a. Asshown, the contact holes 30 a may have slanted sidewalls.

Referring to (a) and (b) of FIG. 6, a second contact layer 31 is formedon the second conductive type semiconductor layer 29. The second contactlayer 31 is formed on the semiconductor stack 30 except for regionscorresponding to the plurality of contact holes 30 a.

The second contact layer 31 may include a transparent conductive oxidefilm such as indium tin oxide (ITO) or a reflective metal layer such assilver (Ag) or aluminum (Al). The second contact layer 31 may becomposed of a single layer or multiple layers. The second contact layer31 may also be configured to form an ohmic contact with the secondconductive type semiconductor layer 29.

The second contact layer 31 may be formed before or after formation ofthe plurality of contact holes 30 a.

Referring to (a) and (b) of FIG. 7, a first insulation layer 33 isformed to cover the second contact layer 31. The first insulation layer33 may cover the side surface of the semiconductor stack 30 exposed tothe chip separation region 30 b while covering the sidewalls of theplurality of contact holes 30 a. Here, the first insulation layer 33 mayhave openings 33 a, which expose the first conductive type semiconductorlayer 25 in the plurality of contact holes 30 a.

The first insulation layer 33 may be composed of a single layer ormultiple layers, such as a silicon oxide or silicon nitride film.Alternatively, the first insulation layer 33 may be composed of adistributed Bragg reflector, which is formed by alternately stackinginsulation layers having different indices of refraction. For example,the first insulation layer 33 may be formed by alternately stackingSiO₂/TiO₂ or SiO₂/Nb₂O₅. Further, the first insulation layer 33 may beformed to provide a distributed Bragg reflector having high reflectivityover a wide wavelength range of blue, green, and red light by adjustingthe thickness of each of the insulation layers.

Referring to (a) and (b) of FIG. 8, a first contact layer 35 is formedon the first insulation layer 33. The first contact layer 35 includescontact sections 35 a contacting the first conductive type uppersemiconductor layer 25 exposed in the contact holes 30 a, and aconnecting section 35 b connecting the contact sections 35 a to eachother. The first contact layer 35 may be composed of a reflective metallayer, but is not limited thereto.

The first contact layer 35 is formed on some regions of thesemiconductor stack 30, so that the first insulation layer 33 is exposedon other regions of the semiconductor stack 30 where the first contactlayer 35 is not formed.

Referring to (a) and (b) of FIG. 9, a second insulation layer 37 isformed on the first contact layer 35. The second insulation layer 37 maybe composed of a single layer or multiple layers, such as a siliconoxide or silicon nitride film. Further, the second insulation layer 37may be composed of a distributed Bragg reflector, which is formed byalternately stacking insulation layers having different indices ofrefraction.

The second insulation layer 37 may cover the first contact layer 35while covering the first insulation layer 33. The second insulationlayer 37 may also cover the side surface of the semiconductor stack 30in the chip separation region 30 b.

The second insulation layer 37 has an opening 37 a which exposes thefirst contact layer 35. Further, the second insulation layer 37 and thefirst insulation layer 33 are formed with an opening 37 b, which exposesthe second contact layer 31.

Referring to (a) and (b) of FIG. 10, first and second electrode pads 39a, 39 b are formed on the second insulation layer 37. The firstelectrode pad 39 a is connected to the first contact layer 35 throughthe opening 37 a and the second electrode pad 39 b is connected to thesecond contact layer 31 through the opening 37 b.

The first electrode pad 39 a is separated from the second electrode pad39 b and each of the first and second electrode pads 39 a, 39 b may havea relatively large area from a top perspective, for example, an area notless than ⅓ of the area of the LED package.

Referring to FIG. 11, an insulation layer 43 is formed on the first andsecond electrode pads 39 a, 39 b. The insulation layer 43 covers thefirst and second electrode pads 39 a, 39 b and has grooves which exposeupper surfaces of the electrode pads 39 a, 39 b. Further, the insulationlayer 43 may have a groove which exposes the second insulation layer 37between the first and second electrode pads 39 a, 39 b.

Then, first and second bump 45 a, 45 b are formed in the grooves of theinsulation layer 43, and a dummy bump 45 c may be formed between thefirst bump and the second bump.

The bumps may be formed by plating, for example, electroplating, using ametallic material. If necessary, a seed layer for plating may also beformed.

After the first and second bumps 45 a, 45 b are formed, the insulationlayer 43 may be removed. For example, the insulation layer 43 may beformed of a polymer such as photoresist and may be removed after thebumps are formed. Alternatively, the insulation layer 43 may remain toprotect the side surfaces of the first and second bumps 45 a, 45 b.

In the present exemplary embodiment, the insulation layer 43 isillustrated as being directly formed on the first and second electrodepads 39 a, 39 b. In other exemplary embodiments, another insulationlayer may be formed to cover the first and second electrode pads 39 a,39 b. The other insulation layer may be configured to have openingsexposing the first and second electrode pads 39 a, 39 b. Then, theprocesses of forming the insulation layer 43 and the bumps may becarried out.

Referring to FIG. 12, the growth substrate 21 is removed and awavelength convertor 51 is attached to the first conductive typesemiconductor layer 25. The growth substrate 21 may be removed by anoptical technique such as laser lift-off (LLO), mechanical polishing orchemical etching.

Then, the exposed surface of the first conductive type semiconductorlayer 25 is subjected to anisotropic etching such asphotoelectrochemical (PEC) etching to form a roughened surface on theexposed first conductive type semiconductor layer 25.

Meanwhile, the wavelength convertor such as a phosphor sheet containingphosphors may be attached to the first conductive type semiconductorlayer 25.

Alternatively, the growth substrate 21 may contain an impurity forconverting a wavelength of light generated in the active layer 27. Inthis case, the growth substrate 21 may be used as the wavelengthconvertor 51.

Then, the LED package structure is divided into individual packagesalong the chip separation region 30 b, thereby providing finished LEDpackages 100. At this time, the second insulation layer 37 is cuttogether with the wavelength convertor 51 so that cut planes thereof canbe formed in a line.

FIG. 13 is a sectional view showing a method of fabricating the LEDpackage 200 according to the second exemplary embodiment of the presentinvention.

Referring to FIG. 13, in the method of fabricating the LED package 200according to the present exemplary embodiment, the processes until thefirst and second electrode pads 39 a, 39 b are formed are the same asthose of the method of fabricating the LED package 100 described above(FIGS. 10 (a) and (b)).

After the first and second electrode pads 39 a, 39 b are formed, aninsulation layer 49 is formed to cover the first and second electrodepads 39 a, 39 b. The insulation layer 49 may cover side surfaces of thefirst and second electrode pads 39 a, 39 b to protect the first andsecond electrode pads 39 a, 39 b. The insulation layer 49 has openingswhich expose the first and second electrode pads 39 a, 39 b. Additionalmetal layers 67 a, 67 b are then formed in the openings. The additionalmetal layers 67 a, 67 b may be composed of a bonding metal.

The substrate 61 is bonded to the first and second electrode pads 39 a,39 b. The substrate 61 may have through-holes, in which the first andsecond bumps 65 a, 65 b may be formed. Further, the first and secondbumps may be formed at distal ends thereof with pads 69 a, 69 b. Thesubstrate 61 having the first and second bumps 65 a, 65 b and the pads69 a, 69 b may be separately prepared and bonded to a wafer having thefirst and second electrode pads 39 a, 39 b.

Then, as described with reference to FIG. 12, the growth substrate 21 isremoved and a wavelength convertor 51 may be attached to the firstconductive type semiconductor layer 25, followed by division of the LEDpackage structure into individual LED packages. As a result, thefinished LED packages 200 as described in FIG. 2 are provided.

FIG. 14 is a sectional view of an LED package 300 according to a thirdexemplary embodiment of the present invention.

Referring to FIG. 14, the LED package 300 may include a semiconductorstack 130, which is divided into a plurality of light emitting cells(only two light emitting cells S1, S2 are shown herein), a first contactlayer 135, a second contact layer 131, a first insulation layer 133, asecond insulation layer 137, a first electrode pad 139 a, a secondelectrode pad 139 b, a connector 139 c connecting adjacent lightemitting cells to each other in series, a first bump 145 a and a secondbump 145 b. Further, the LED package 300 may include a third insulationlayer 141, an insulation layer 143, a dummy bump 145 c, a wavelengthconvertor 151, and additional metal layers 140 a, 140 b.

The semiconductor stack 130 includes a first conductive type uppersemiconductor layer 125, an active layer 127, and a second conductivetype lower semiconductor layer 129. The semiconductor stack 130 of thepresent exemplary embodiment is similar to the semiconductor stack 30described in FIG. 1, and a detailed description thereof will be omittedherein.

Each of the light emitting cells S1, S2 has a plurality of contact holes130 a (see FIG. 18( b)) extending through the second conductive typelower semiconductor layer 129 and the active layer 127 to expose thefirst conductive type upper semiconductor layer, and the first contactlayer 135 contacts the first conductive type upper semiconductor layer125 exposed in the plurality of contact holes. The light emitting cellsS1, S2 are separated from each other by a cell separation region 130 b(see FIG. 18( b)).

The second contact layer 131 contacts the second conductive type lowersemiconductor layer 129 of each of the light emitting cells S1, S2. Thesecond contact layer 131 includes a reflective metal layer to reflectlight generated in the active layer 127. Further, the second contactlayer 131 may form an ohmic contact with the second conductive typelower semiconductor layer 129.

The first insulation layer 133 covers the second contact layer 131.Further, the first insulation layer 133 covers a sidewall of thesemiconductor stack 130 exposed in the plurality of contact holes 130 a.In addition, the first insulation layer 133 may cover a side surface ofeach of the light emitting cells S1, S2. The first insulation layer 133insulates the first contact layer 135 from the second contact layer 131while insulating the second conductive type lower semiconductor layer129 and the active layer 127 exposed in the plurality of contact holes130 a from the first contact layer 35. The first insulation layer 133may be composed of a single layer or multiple layers, such as a siliconoxide or silicon nitride film. Furthermore, the first insulation layer133 may be composed of a distributed Bragg reflector, which is formed byalternately stacking insulation layers having different indices ofrefraction, for example, SiO₂/TiO₂ or SiO₂/Nb₂O₅.

The first contact layer 135 is located under the first insulation layer133 and contacts the first conductive type upper semiconductor layer 125through the first insulation layer 133 in the plurality of contact holes130 a in each of the light emitting cells S1, S2. The first contactlayer 135 includes contact sections 135 a contacting the firstconductive type upper semiconductor layer 125, and a connecting section135 b connecting the contact sections 135 a to each other. Therefore,the contact sections 135 a are electrically connected to each other bythe connecting section 135 b. The first contact layers 135 located underthe respective light emitting cells S1, S2 are separated from each otherand formed under some regions of the first insulation layer 133. Thefirst contact layer 135 may be composed of a reflective metal layer.

The second insulation layer 137 covers the first contact layer 135 underthe first contact layer 135. In addition, the second insulation layer137 may cover the first insulation layer 133 while covering the sidesurface of each of the light emitting cells S1, S2. The secondinsulation layer 137 may be composed of a single layer or multiplelayers. Alternatively, the second insulation layer 37 may be composed ofa distributed Bragg reflector.

The first electrode pad 139 a and the second electrode pad 139 b arelocated under the second insulation layer 137. The first electrode pad139 a may be connected to the first contact layer 135 of a first lightemitting cell S1 through the second insulation layer 137. Further, thesecond electrode pad 139 b may be connected to the second contact layer31 of a second light emitting cell S2 through the second insulationlayer 137 and the first insulation layer 133.

The connector 139 c is located under the second insulation layer 137 andelectrically connects two adjacent light emitting cells S1, S2 to eachother through the second insulation layer 137. The connector 139 c mayconnect the second contact layer 131 of one light emitting cell S1 tothe first contact layer 135 of another light emitting cell S2 adjacentthereto, so that the two light emitting cells S1, S2 are connected inseries to each other.

In the present exemplary embodiment, two light emitting cells S1, S2 areillustrated. However, it should be understood that two or more lightemitting cells may be connected in series to each other by a pluralityof connectors 139 c. Here, the first and second electrode pads 139 a,139 b may be connected in series to the light emitting cells S1, S2located at opposite ends of such series array.

Meanwhile, the third insulation layer 141 may cover the first electrodepad 139 a, the second electrode pad 139 b and the connector 139 c underthe first electrode pad 139 a, the second electrode pad 139 b and theconnector 139 c. The third insulation layer 141 may have an openingexposing the first electrode pad 139 a and the second electrode pad 139b. The third insulation layer 141 may be formed of a silicon oxide orsilicon nitride film.

The first bump 145 a and the second bump 145 b are located under thefirst and second electrode pads 139 a, 139 b, respectively. The firstand second bumps 145 a, 145 b may be formed by plating. The first andsecond bumps 145 a, 145 b are terminals electrically connected to acircuit board such as an MC-PCB and have distal ends coplanar with eachother. In addition, the first electrode pad 139 a may be formed at thesame level as that of the second electrode pad 139 b, so that the firstbump 45 a and the second bump 45 b may also be formed on the same plane.Therefore, the first and second bumps 45 a, 45 b may have the sameheight.

The additional metal layers 140 a, 140 b may be interposed between thefirst bump 145 a and the first electrode pad 139 a and between thesecond bump 145 b and the second electrode pad 139 b. Here, theadditional metal layers 140 a, 140 b are provided to form the first andsecond electrode pads 139 a, 139 b to be higher than the connector 139 cand may be located inside openings of the third insulation layer 141.The first and second electrode pads 139 a, 139 b and the additionalmetal layers 140 a, 140 b may constitute final electrode pads.

Meanwhile, the dummy bump 145 c may be located between the first bump145 a and the second bump 145 b. The dummy bump 145 c may be formedtogether with the first and second bump 145 a, 145 b to provide a heatpassage for discharging heat from the light emitting cells S1, S2. Thedummy bump 145 c is separated from the connector 139 c by the thirdinsulation layer 141.

The insulation layer 143 may cover side surfaces of the first and secondbumps 145 a, 145 b. The insulation layer 143 may also cover a sidesurface of the dummy bump 145 c. In addition, the insulation layer 143fills spaces between the first bump 145 a, the second bump 145 b and thedummy bump 145 c to prevent moisture from entering the semiconductorstack 130 from outside. Although the insulation layer 143 may beconfigured to cover the overall side surfaces of the first and secondbumps 145 a, 145 b, the invention is not limited thereto. Alternatively,the insulation layer 143 may cover the side surfaces of the first andsecond bumps 145 a, 145 b except for some regions of the side surfacenear distal ends of the first and second bumps.

The wavelength convertor 151 may be located on the light emitting cellsS1, S2. The wavelength convertor 151 may contact an upper surface of thefirst conductive type upper semiconductor layer 125. The wavelengthconvertor 151 also covers a cell separation region 130 b and a chipseparation region. The wavelength convertor 151 may be a phosphor sheethaving a uniform thickness without being limited thereto. Alternatively,the wavelength converter 51 may be a substrate, for example, a sapphiresubstrate or a silicon substrate, which is doped with an impurity forwavelength conversion.

In the present embodiment, the side surfaces of the light emitting cellsS1, S2 are covered with a protective insulation layer. The protectiveinsulation layer may include, for example, the first insulation layer133 and/or the second insulation layer 137. In addition, the firstcontact layer 135 may be covered with the second insulation layer 137 tobe protected from external environment and the second contact layer 131may be covered with the first insulation layer 133 and the secondinsulation layer 137 to be protected from external environment. Further,the first and second electrode pads 139 a, 139 b are also protected by,for example, the third insulation layer 141. Accordingly, it is possibleto prevent deterioration of the light emitting cells S1, S2 due tomoisture.

The wavelength convertor 151 may be attached to the first conductivetype upper semiconductor layer 125 at a wafer-level, and then dividedtogether with the protective insulation layer during a chip separationprocess (or package separation process). Therefore, a side surface ofthe wavelength convertor 151 may be in a line with the protectiveinsulation layer. Further, the side surface of the wavelength convertor151 may be in a line with a side surface of the insulation layer 143.

FIG. 15 is a schematic sectional view of a light emitting diode package400 according to a fourth exemplary embodiment of the present invention.

Referring to FIG. 15, the LED package 400 is similar to the LED package300 according to the above exemplary embodiment. In present exemplaryembodiment, however, first and second bumps 165 a, 165 b are formed in asubstrate 161.

Specifically, the substrate 161 includes through-holes, which have thefirst and second bumps 165 a, 165 b formed therein, respectively. Thesubstrate 161 is an insulation substrate, for example, a sapphiresubstrate or a silicon substrate, but is not limited thereto.

The substrate 161 having the first and second bumps 165 a, 165 b may beattached to a third insulation layer 141, and the first and second bumps165 a, 165 b may be connected to first and second electrode pads 139 a,139 b, respectively. Here, the first and second bumps 165 a, 165 b maybe bonded to additional metal layers 140 a, 140 b, respectively.

FIG. 16 is a sectional view of a light emitting diode module includingthe LED packages 300 according to the third exemplary embodiment on acircuit board.

Referring to FIG. 16, the LED module includes a circuit board 171, forexample, an MC-PCB, the LED package 300, and a lens 181. The circuitboard 171, for example, the MC-PCB, has connection pads 173 a, 173 b formounting the LED packages 300 thereon. The first and second bumps 145 a,145 b (see FIG. 14) of the LED package 300 are connected to theconnection pads 73 a, 73 b, respectively.

A plurality of LED packages 300 may be mounted on the circuit board 171and the lens 181 may be disposed on the LED packages 300 to adjust anorientation angle of light emitted from the LED packages 300.

In other exemplary embodiments, instead of the LED packages 300, thelight emitting diode packages 400 may be mounted on the circuit board.

FIG. 17 to FIG. 25 show a method of fabricating the LED package 300according to the third exemplary embodiment. In FIG. 18 to FIG. 23, (a)is a plan view and (b) is a sectional view taken along line A-A of (a).

Referring to FIG. 17, a semiconductor stack 130, which includes a firstconductive type semiconductor layer 125, an active layer 127 and asecond conductive type semiconductor layer 129, is formed on a growthsubstrate 121. The growth substrate 121 and the semiconductor stack 130are similar to the substrate 21 and the semiconductor stack 30 describedwith reference to FIG. 4, and a detailed description thereof will thusbe omitted herein.

Referring to (a) and (b) of FIG. 18, the semiconductor stack 130 ispatterned to form a chip (package) separation region 130 c and a cellseparation region 130 b while patterning the second conductive typesemiconductor layer 129 and the active layer 127 to form light emittingcells S1, S2, each having a plurality of contact holes 130 a exposingthe first conductive type semiconductor layer 125. The semiconductorstack 130 may be patterned by photolithography and etching processes.

The chip separation region 130 c is a region for dividing the LEDpackage structure into individual LED packages and side surfaces of thefirst conductive type semiconductor layer 125, the active layer 127 andthe second conductive type semiconductor layer 129 are exposed at thechip separation region 130 c. Advantageously, the chip separation region130 c and the cell separation region 130 b may be configured to exposethe substrate 121 without being limited thereto.

The plurality of contact holes 130 a may have a circular shape, but isnot limited thereto. The contact holes 130 may have a variety of shapes.The second conductive type semiconductor layer 129 and the active layer127 are exposed to sidewalls of the plurality of contact holes 130 a.The contact holes 130 a may have slanted sidewalls.

Referring to (a) and (b) of FIG. 19, a second contact layer 131 isformed on the second conductive type semiconductor layer 129. The secondcontact layer 131 is formed on the semiconductor stack 130 in each ofthe light emitting cells S1, S2 except for regions corresponding to theplurality of contact holes 130 a.

The second contact layer 131 may include a transparent conductive oxidefilm such as indium tin oxide (ITO) or a reflective metal layer such assilver (Ag) or aluminum (Al). The second contact layer 131 may becomposed of a single layer or multiple layers. The second contact layer131 may also be configured to form an ohmic contact with the secondconductive type semiconductor layer 129.

The second contact layer 131 may be formed before or after the formationof the plurality of contact holes 130 a

Referring to (a) and (b) of FIG. 20, a first insulation layer 133 isformed to cover the second contact layer 131. The first insulation layer133 may cover the side surface of each of the light emitting cells S1,S2 while covering the sidewalls of the plurality of contact holes 130 a.Here, the first insulation layer 133 may have openings 133 a, whichexpose the first conductive type semiconductor layer 125 in theplurality of contact holes 130 a.

The first insulation layer 133 may be composed of a single layer ormultiple layers, such as a silicon oxide or silicon nitride film. Inaddition, the first insulation layer 133 may be composed of adistributed Bragg reflector, which is formed by alternately stackinginsulation layers having different indices of refraction. For example,the first insulation layer 133 may be formed by alternately stackingSiO₂/TiO₂ or SiO₂/Nb₂O₅. Further, the first insulation layer 133 may beformed to provide a distributed Bragg reflector having high reflectivityover a wide wavelength range of blue, green, and red light by adjustingthe thickness of each of the insulation layers.

Referring to (a) and (b) of FIG. 21, a first contact layer 135 is formedon the first insulation layer 133. The first contact layer 135 is formedon each of the light emitting cells S1, S2, and includes contactsections 35 a contacting the first conductive type upper semiconductorlayer 125 exposed in the contact holes 130 a and a connecting section135 b connecting the contact sections 135 a to each other. The firstcontact layer 135 may be composed of a reflective metal layer, but isnot limited thereto.

The first contact layer 135 is formed on some regions of each of thelight emitting cells S1, S2, so that the first insulation layer 133 isexposed at other regions of the semiconductor stack 130 where the firstcontact layer 135 is not formed.

Referring to (a) and (b) of FIG. 22, a second insulation layer 137 isformed on the first contact layer 135. The second insulation layer 137may be composed of a single layer or multiple layers, such as a siliconoxide or silicon nitride film. Alternatively, the second insulationlayer 137 may be composed of a distributed Bragg reflector, which isformed by alternately stacking insulation layers having differentindices of refraction.

The second insulation layer 137 may cover the first contact layer 135while covering the first insulation layer 133. The second insulationlayer 137 may also cover the side surface of the each of the lightemitting cells S1, S2. In addition, the second insulation layer 137 mayfill in the chip separation region 130 c and the cell separation region130 b.

The second insulation layer 137 has an opening 137 a which exposes thefirst contact layer 135 of each of the light emitting cells S1, S2.Further, the second insulation layer 137 and the first insulation layer133 are formed with an opening 137 b, which exposes the second contactlayer 131.

Referring to (a) and (b) of FIG. 23, a connector 139 c and first andsecond electrode pads 139 a, 139 b are formed on the second insulationlayer 137. The first electrode pad 139 a is connected to the firstcontact layer 135 of a first light emitting cell S1 through the opening137 a and the second electrode pad 139 b is connected to the secondcontact layer 131 of a second light emitting cell S2 through the opening137 b. Further, the connector 139 c connects the first contact layer 135and the second contact layer 131 of adjacent light emitting cells S1, S2to each other in series through the openings 137 a, 137 b.

Referring to FIG. 24, a third insulation layer 141 is formed on thefirst and second electrode pads 139 a, 139 b and the connector 139 c.The third insulation layer 141 covers the first and second electrodepads 139 a, 139 b and the connector 139 c, and has grooves which exposeupper surfaces of the electrode pads 139 a, 139 b. Meanwhile, the thirdinsulation layer 141 may have additional metal layers 140 a, 140 bformed in the grooves thereof. The additional metal layers 140 a, 140 bincrease the height of the electrode pads 139 a, 139 b, such that finalelectrode pads may have a greater height than the connector 139 c. Theadditional metal layers 140 a, 140 b may be formed before the formationof the third insulation layer 141. Upper surfaces of the additionalmetal layers 140 a, 140 b may be substantially coplanar with an uppersurface of the third insulation layer 141.

Referring to FIG. 25, a patterned insulation layer 143 is formed on thethird insulation layer 141. The patterned insulation layer 143 hasgrooves, which expose the upper side of the first and second electrodepads 139 a, 139 b, for example, the additional metal layers 140 a, 140b. Further, the patterned insulation layer 143 may have a grooveexposing the third insulation layer 141 between the first electrode pad139 a and the second electrode pad 139 b.

Then, first and second bumps 145 a, 145 b are formed in the grooves ofthe insulation layer 143 and a dummy bump 145 c may be formed betweenthe first and second bumps.

The bumps may be formed by plating, for example, electroplating. Asneeded, a seed layer for plating may also be formed.

After the first and second bumps 145 a, 145 b are formed, the insulationlayer 143 may be removed. For example, the insulation layer 143 may beformed of a polymer such as photoresist and may be removed after thebumps are formed. Alternatively, the insulation layer 143 may remain toprotect the side surfaces of the first and second bumps 145 a, 145 b.

Referring to FIG. 26, the growth substrate 121 is removed and awavelength convertor 151 is attached to the light emitting cells S1, S2.The growth substrate 21 may be removed by an optical technique such aslaser lift-off (LLO), mechanical polishing or chemical etching.

Then, the exposed surface of the first conductive type semiconductorlayer 125 is subjected to anisotropic etching such as PEC etching toform a roughened surface on the exposed first conductive typesemiconductor layer 125.

Meanwhile, the wavelength convertor 151, such as a phosphor sheetcontaining phosphors, may be attached to the first conductive typesemiconductor layer 125

Alternatively, the growth substrate 121 may contain an impurity forconverting a wavelength of light generated in the active layer 127. Inthis case, the growth substrate 121 may be used as the wavelengthconvertor 151.

Then, the LED package structure is divided into individual packagesalong the chip separation region 130 c, thereby providing finished LEDpackages 300. At this time, the second insulation layer 137 is cuttogether with the wavelength convertor 151 so that cut planes thereofcan be formed in a line.

FIG. 27 is a sectional view explaining a method of fabricating the LEDpackage 400 according to the fourth exemplary embodiment of theinvention.

Referring to FIG. 27, in the method of fabricating the LED package 400according to this embodiment, the processes until the third insulationlayer 141 and the additional metal layers 140 a, 1140 b are formed arethe same as those of the method of fabricating the LED package 300described above (FIG. 24).

In the present exemplary embodiment, the substrate 161 is bonded to thethird insulation layer 141. The substrate 161 may have through-holes, inwhich the first and second bumps 165 a, 165 b may be formed. Further,the first and second bumps 165 a, 165 b may be formed at distal endsthereof with pads (not shown). In addition, the substrate 161 may havegrooves partially formed on a lower surface thereof and filled with ametallic material 165 c. The metallic material 165 c improves substrateheat dissipation.

Alternatively, the substrate 161 having the first and second bumps 165a, 165 b may be separately prepared and bonded to a wafer having thefirst and second electrode pads 139 a, 139 b. The first and second bumps165 a, 165 b may be electrically connected to first and second electrodepads 139 a, 139 b, respectively.

Then, as described with reference to FIG. 26, the growth substrate 121is removed and the wavelength convertor 151 may be attached to the lightemitting cells S1, S2, followed by division of the LED package structureinto individual LED packages. As a result, the finished LED packages 400as described in FIG. 15 are provided.

As such, the exemplary embodiments of the invention provide wafer-levelLED packages which can be directly formed on a circuit board for amodule without using a conventional lead frame or printed circuit board.Accordingly, the LED package may have high efficiency and exhibitimproved heat dissipation while reducing time and cost for fabricationof the LED package. In addition, an LED module having the LED packagemounted thereon may have high efficiency and exhibit improved heatdissipation.

Further, the LED package may include a plurality of light emitting cellsconnected in series to each other and arrays connected in reverseparallel to each other. Further, the plurality of light emitting cellsmay be connected to a bridge rectifier and may be used to form a bridgerectifier. Therefore, the LED module including the LED package may beoperated by AC power without a separate AC/DC converter.

Although the invention has been illustrated with reference to someexemplary embodiments in conjunction with the drawings, it will beapparent to those skilled in the art that various modifications andchanges can be made to the invention without departing from the spiritand scope of the invention. Further, it should be understood that somefeatures of a certain embodiment may also be applied to other embodimentwithout departing from the spirit and scope of the invention. Therefore,it should be understood that the embodiments are provided by way ofillustration only and are given to provide complete disclosure of theinvention and to provide thorough understanding of the invention tothose skilled in the art. Thus, it is intended that the invention coversthe modifications and variations provided they fall within the scope ofthe appended claims and their equivalents.

What is claimed is:
 1. A light-emitting diode (LED), comprising: asemiconductor stack comprising a first semiconductor layer, a secondsemiconductor layer, and an active layer disposed between the first andsecond semiconductor layers, the first and second semiconductor layershaving different conductivity types; a first contact layer disposed onthe first type semiconductor layer; a second contact layer disposed onthe second type semiconductor layer; a first insulation layer coveringthe second contact layer, sidewalls of the active layer, and the secondsemiconductor layer, and contacting the first contact layer, the firstinsulation layer comprising a first opening exposing the firstsemiconductor layer and a second opening exposing the second contactlayer; a second insulation layer is disposed on the first insulationlayer; a first bump disposed on a first side of the semiconductor stack,the first bump being electrically connected to the first contact layer;a second bump disposed on the first side of the semiconductor stack, thesecond bump being electrically connected to the second contact layer;and a third insulation layer disposed on side surfaces of the first bumpand the second bump.
 2. The LED of claim 1, wherein the secondinsulation layer is disposed directly on the first contact layer.
 3. TheLED of claim 1, further comprising a wavelength conversion layerdisposed directly on the semiconductor stack.
 4. The LED of claim 3,wherein the wavelength converter is disposed on a second side ofsemiconductor stack opposite to the first side.
 5. The LED of claim 4,wherein the wavelength converter comprises a phosphor sheet or animpurity-doped material.
 6. The LED of claim 4, wherein the wavelengthconverter comprises a side surface that is substantially coplanar withside surfaces of the first and second insulation layers.
 7. The LED ofclaim 6, wherein the side surfaces of the first and second insulationlayers are substantially coplanar with a side surface of the thirdinsulation layer.
 8. The LED of claim 1, wherein at least one of thefirst insulation layer and the second insulation layer comprises adistributed Bragg reflector.
 9. The LED of claim 1, wherein the firstinsulation layer separates the first contact layer from second contactlayer.
 10. The LED of claim 1, wherein the third insulation layercomprises a polymer.
 11. The LED of claim 1, further comprising a dummybump disposed between the first bump and the second bump.
 12. The LED ofclaim 1, wherein: the first bump and the second bump are terminalscomprising substantially coplanar distal ends; and the first bump andthe second bump are electrically connected to a circuit board.
 13. TheLED of claim 12, wherein the circuit board comprises a metal coreprinted circuit board (MC-PCB).
 14. The LED of claim 1, wherein thefirst bump and the second bump protrude from the third insulation layer.15. The LED of claim 1, wherein the first bump is formed by plating. 16.The LED of claim 1, further comprising: a first electrode pad disposedbetween the second insulation layer and the first bump; and a secondelectrode pad disposed between the second insulation layer and thesecond bump.
 17. The LED of claim 16, wherein: the first electrode padextends through the second insulation layer to contact the first contactlayer; and the second electrode pad extends through the secondinsulation layer to contact the second contact layer.
 18. The LED ofclaim 1, wherein the first semiconductor layer comprises a roughenedsurface.
 19. The LED of claim 1, further comprising a contact holeformed through the second semiconductor layer and the active layer toexpose the first opening, wherein the first contact layer iselectrically insulated from the second semiconductor layer and theactive layer in the contact hole.
 20. The LED of claim 19, wherein thefirst contact layer contacts the first type semiconductor layer throughthe first opening.